Shuttle nose pneumatic fastener driver

ABSTRACT

The invention relates to a fluid-pressure-operated device for driving fasteners through material whereby a shuttle piston pushes a shuttle towards the material to compress the material against a fixed clincher and a driver piston pushes a driver blade towards the material to drive a fastener into the material after the shuttle has compressed it. In the embodiment described in detail the pistons are of the differential type and move linearly and with a constant angularity with respect to the clincher.

United States tet SHUTTLE NOSE PNEUMATIC FASTENEIR DRllVElR 10 Claims, 3 Drawing Figs.

US. Cl 227/124, 227/130, 227/153 Int. Cl 1325c 5/02 Field of Search 227/130, 124, 153

[56] References Cited UNITED STATES PATENTS 1,855,266 4/1932 Van Eps 91/169 2,687,522 8/1954 .luilfs 1 227/130 X 2,774,968 12/1956 Osborne et al.... 227/130 Primary Examiner Cranville Y. Custer, Jr. Attorney-Cushman, Darby & Cushman m 57 A3 M 6/ 54 i y I Z as I 72 24 i 4 77 I ,1 My; 6,;

j/ a/ 9n a I I I 1 I I r 59 e 54 a! PATENTEDAuaemn SHEET 1 OF 2 SHUTTLE NOSE PNEUMATIC F ASTENER DRIVER BRIEF DESCRIPTION OF THE PRIOR ART AND SUMMARY OF THE INVENTION The invention relates to a fluid-pressure-operated device for driving fasteners through material whereby a first differential piston pushes a shuttle before it towards the material to cause the shuttle to compress the material against a fixed clincher and-a second differential piston pushes a driver blade towards the material to drive the fastener into the material. Fluid pressure has been used in the past for operating many types of machinery including devices for driving fasteners such as staplers. Many materials, however, cannot be adequately fastened unless the material is compressed before the fastener is driven. Although in staplers with a driver blade the driver blade compresses the material somewhat, this cornpression may be insufficient and the blade may injure some materials, such as those which are spongy.

In the present invention, this problem is overcome by driving the shuttle, which contains the raceway within which the fastener itself is being driven, towards the material to compress the material before the fastener is driven through the material. Since the shuttle presents much more surface area to the material than the driver blade alone, the material can be satisfactorily compressed without harming the material.

A number of small hand-operated fastener driver devices in the prior art have utilized arrangements whereby either the clincher was rotated in an arc to meet the fastener or the driver itself was rotated in an arc. Such arrangements have proved unsatisfactory because of difficulty in properly clinching the fastener and have been overly complex and costly.

In contrast, in the embodiment discussed below, the fastener is driven through the material against a fixed clincher. Both pistons, which may be of the differential type, move linearly and maintain a substantially constant angularity with respect'to the fixed clincher during movement toward and away from the material. In addition, the stapler described below, which represents only one embodiment of the invention, is a relatively portable lightweight and inexpensive device which can be used in fastening a wide variety of objects and materials with a single stroke, including those which are not readily compressible. This stapler utilizes a single poppet valve which can be shifted between two positions by manually squeezing a valve trigger. In the first position, a net pressure away from the material is exerted on the two differential pistons so that the pistons are held in an inoperative position andin the second position, the fluid pressure is also directed against the pistons, overcoming the net pressure holding them in the inoperative position so that both pistons are pushed rapidly toward the material.

As the pistons move toward the material the driver blade strips a staple from a number of staples stored in a magazine and places it in a suitable raceway. Furthermore, the driver piston moves more rapidly than the shuttle piston so that the driver blade contacts the staple in the raceway at all times thereby preventing the staple from tumbling. Despite its slower speed, the shuttle piston contacts the material first because of the lesser distance which the piston travels and compresses it before the driver blade drives the staple through the material whereupon it is clinched against a fixed clincher.

The operation then is wholly automatic; by squeezing the trigger, the shuttle piston is driven toward the material to compact the material against the fixed clincher and the driver piston driven towards the material to drive the staple through the material. Then, after the trigger is released both pistons are caused to move away from the material back to the inoperative position from which a new staple can then be driven. With this simple and effective arrangement, staples can be driven rapidly and easily through a variety of materials.

Other objects and purposes of the invention will become clear after reading the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows a cutaway view of one embodiment of the invention with the'driver and shuttle piston held in the inoperative position.

FIG. 2 shows a cutaway view of one embodiment of the invention with the driver and shuttle pistons shown at the terminal portion of the compressing and stapling movement.

FIG. 3 shows a view of one embodiment of the invention with a fixed clincher.

DETAILED DESCRIPTION OF THE DRAWINGS Reference is now made to FIGS. 1, 2 and 3 which disclose one embodiment of the present invention. In this embodiment, a stapler is operated by manually squeezing the valve trigger 20, so that it rotates from the inoperative position shown in FIG. 1 in a counterclockwise direction around a transverse pin 22, which serves to hold the valve trigger in place, to the operative position shown in FIG. 2. The rotation of the valve trigger 20 then operates the poppet valve 24 to initiate the compressing of the material 25 followed by the driving of a fastener into the material 25.

When the trigger 20 is in the inoperative position, as shown in FIG. 1, the disklike closure 26 which is mounted on the thin upper stem 28 of the poppet valve 24 seals the bore 30 within which the poppet valve 24 reciprocates. However, fluid freely flows through the passageways 34 and 40 and then into the annular region 38 and from there through the port 42 into the annular region 44. Normally fluid under pressure, such as air, is forced into the reservoir 50 which is located within a hollow handle member 51 from some exterior source (not shown).

The fluid then passes from the reservoir 50 through thepassageways 34 and 40 and the port 42 into the regions 38 and 44 to assist in maintaining the differential driver piston 52 and the differential shuttle piston 54 in position firmly against the bumpers 57 and 59 mounted on and adjacent to the cap 56 of the casing 60 as described below.

Both the pistons are disposed within a hollow casing 60 which has a cylindrical cavity 61 within which the hollow shut- ,tle piston 54 reciprocates. Similarly, the shuttle piston 54 hasa hollow cylindrical cavity 62 within which the differential driver pistons 52 reciprocates. Both pistons 52 and 54 may be conventional differential pistons whose operation are well known and hence their structure and operation will not be discussed in detail herein.

Of course, it is not necessary that the material be located below the pistons and that the pistons move downward to meet it. The material can be disposed in any direction with regard to the pistons and it is only necessary that the pistons move toward and away from the material. However, in describing the operation of this embodiment, it will be assumed that the material is below the pistons.

The pressure of the fluid in the annular region 44 surrounding the differential driver piston 52 pushes against the driver piston 52 but, since a greater surface area of the piston 52 is available for the fluid to push on upward away from the material than downward toward the material, the fluid pressure holds the piston 52 snugly against the bumper 59. Annular gaskets 63 and 64 also assist in maintaining the driver piston 52 against the bumper 59, which is attached to the cap 56 of the casing 60, by contacting the walls of the cavity 62 which is within the shuttle piston 54 and frictionally opposing movement. Similarly, gaskets and 72 assist in preventing the shuttle piston 54 from moving by frictionally contacting the walls of the cylindrical cavity 61 in the casing 60.

When the valve trigger 20 is manually rotated counter clockwise to the position shown in FIG. 2, thereby pushing the poppet valve 24 up, fluid freely enters the unsealed bore 30. Since the bore 30 is connected to the region 76 about the top of the driver and shuttle pistons 52 and 54 through passageway 78, fluid now passes through the unsealed bore 30 and the passageway 78 and exerts a downward force urging the pistons toward the material. Since the area of the two pistons upon which the fluid pushes downward in region 76 exceeds the area upon which the fluid pushes upward in regions 38 and 44, a net downward force results and the pistons move downward. The upward movement of the thick lower stem 80 also blocks the port 79 which is open to the atmosphere, preventing the fluid from passing out of the bore 30 directly into the atmosphere.

Since the total force urging the pistons toward the material is now more than sufficient to overcome the combined frictional resistance of the gaskets and the upward force exerted by the compressed air in regions 38 and 44, both differential pistons 52 and 54 begin to move rapidly downward. Because of differences in weight and surface area upon which the fluid pushes, the driver piston 52 moves more rapidly than the shuttle piston 54, moving roughly one and three-quarters inches for every inch the shuttle piston 54 moves with the result that the driver blade 81 remains in contact with the stripped staple preventing tumbling or misaligning. However, since the shuttle piston 54 does not have as far to travel, it arrives at the material 25 first and compresses it to the extent shown in FIG. 2 before the driver blade 81 pushes the staple through the material 25. It will of course be understood that the exact difference in speed is related to the distances the shuttle piston 54 and the driver piston 52 must move and is therefore solely a matter of design which can be varied to suit design and engineering requirements.

The driver piston 52 has a driver blade 81 of metal or other material which it pushes before it as it descends, and which may be attached to the driver piston 52 by any convenient means, such as welding. Similarly, the shuttle piston 54 is attached to shuttle 82. Although in this embodiment, the shuttle 82 and the shuttle piston 54 are threaded so that the threads serve to bind them together, any convenient method may be used to connect the shuttle piston 54 and the shuttle 82. Furthermore, in this embodiment, the shuttle 82 is comprised of an upper member 83 and a lower nose 84, although the shuttle 82 can also be constructed in one piece ifdesired.

As the driver piston 52 moves downward, the driver blade 81 strips a single staple and places it in the shuttle raceway 87 formed within the lower nose 84 of the shuttle 82. In this embodiment, this raceway 87 is formed in the nose 84 ofthe shuttle 82 so as to accommodate a single staple without allowing the staple to twist or misalign, although the invention is not limited to devices which drive a single fastener. Since the driver piston 52 is moving more rapidly than the shuttle piston 54, the driver blade 81 has time to position the staple in the raceway 87 before the shuttle nose 84 contacts the material 25. Because ofits greater downward speed the driver blade 81 pushes downward at all times on the staple in the raceway 87 from the time that the staple is stripped and placed in raceway 87 until the staple is clinched. Of course at the same time that the driver blade 81 is pushing the staple through the raceway 87 in the nose 84, the nose itself is being pushed downward at a slightly lower rate by the shuttle piston 54.

The staples which are to be driven through the material 25 are stored in a magazine 88 which may be of any convenient type suitable for the storing of staples or other fasteners. The staples are presented one at a time or in groups to the driver blade 81 by a spring or other suitable means which advances the staples to a position where they can be individually stripped and placed in the shuttle raceway 87. A guard member 89 is attached to the casing 60 to protect the shuttle nose 84 and driver blade 81 from damage.

The shuttle 82 continues downward without interruption, driven by the shuttle piston 54, until the shuttle nose 84 within which the staple is being pushed downward by the driver blade 81 strikes and compresses the material 25. The cylindrical cavity 61 within which the shuttle piston 54 reciprocates is provided with an annular stop member cushion 90 mounted on a flange 91 ofthe guard member 89 which halts the descent of the shuttle piston 54 after the material 25 has been compressed a predetermined distance. if desired the stop cushion 90 can be removed and the shuttle piston 54 allowed to move downward until the compressive resistance of the material 25 halts its descent or until the flange 91 itself or some other means prevents further downward movement. At the same time that the material 25 is being compressed the driver piston 52 is pushing the staple, which it has stripped, through the raceway 87 in the nose 84 so that, after the shuttle nose 84 has compressed the material 25, the staple will be driven through the material 25 to be clinched thereupon by a fixed clincher 100. A stop member 104 mounted on the upper member 83 of the shuttle 82 serves to halt the descent of the driver piston 52. The attachment of the clincher 100 to the casing 60 is shown in FIG. 3 and the clincher 100 may be of any conventional type which will operate to clinch the staples.

After the staple has been driven into the material 25 the valve trigger 20 is manually released so that it rotates in a clockwise direction around the transverse pin 22 and the poppet valve 24 returns to the inoperative position shown in FIG. 1. The valve trigger 20 may be spring biased so that it returns to the inoperative position automatically, or the poppet valve 24 may be situated, as in this embodiment, so that the fluid pressure exerts a downward force on the valve 24 which is communicated to the valve trigger 20 through the lower stem whenever the closure 26 does not seal the bore 30. The sealing of the bore 30 by closure 26 as the poppet valve 24 moves downward prevents the further passage of fluid into the region 76. In addition, the thick stem 80 returns downward unblocking the port 79 so that region 76 is connected to the atmosphere via passageway 78 and port 79. The pressure in region 76 then abruptly drops to atmospheric pressure as the compressed fluid in region 76 rushes out through the port 79.

The removal ofthe fluid pressure from region 76 results in a net upward force on pistons 52 and 54 from the fluid pressure in regions 38 and 44. Although the port 42 may be blocked until the driver piston 52 is partially ascended, the fluid pressure is immediately pushing upward on the shuttle piston 54. The shuttle piston 54 then begins to ascend, dragging the driver piston 52, which is riding on the stop member 104, with it. After the shuttle piston 54 reaches the bumper 57 of the casing 60, the driver piston 52 continues upward, pushed by the fluid pressure which has now entered the region 44 through the port 42 until the driver piston 52 is firmly in place against the bumper 59.

To summarize, the valve trigger 20 is pivoted eounterclockwise to initiate the stapling action. The poppet valve 24 then moves upward, directing pressure to the top of the differential pistons so that a greater surface area is exposed to the compressed air pushing downward than to the air pushing upward causing the pistons 52 and 54 to immediately descend toward the material 25. The driver blade 81 pushed by the driver piston 52 is stripping a staple and is placing it in the shuttle raceway 87 at the same time as the shuttle piston 54 is pushing the shuttle 82 downward at a slightly lower rate. Since the shuttle has a shorter distance to travel and despite its lower speed, the shuttle nose 84 contacts and compresses the material 25 just before the driver blade 81 pushes the staple through the material 25 where it is clinched by a clincher which is fixed to the casing 60. As soon as the trigger 20 is released the pressure on top of the pistons 52 and 54 is dis sipated and the supporting pressure on the side of the differential pistons overcomes the downward forces so that the pistons 52 and 54 ascend to their initial position.

The embodiment described above is merely an example of the invention and many modifications and additions can be made without departing from the spirit of the invention. For example, other fluids, such as oil or water, could operate the device and other fasteners, such as nails, driven. Many other arrangements can be used to direct the fluid pressure to operate the pistons and it makes no difference whether the material is below the piston or disposed otherwise. Accordingly, the scope of the invention is limited only by the scope ofthe appended claims.

1. A fluid-pressureoperated device for compressing materi al and driving a fastener into said material comprising:

housing means having means therein defining a reservoir and a cylindrical chamber,

first piston means provided in said cylindrical chamber for linear movement therein,said first piston means having a cylindrical chamber and an exposed surface of a first area such that said first piston means moves in said cylindrical chamber to compress said material when fluid is applied to said exposed surface,

second piston means provided in said cylindrical chamber of said first piston for linear movement at a constant angular relationship with respect to said first piston means and independently of said first piston means, said second piston means having an exposed surface of a second area such that said second piston means moves in said cylindrical chamber of said first piston to drive said fastener when fluid pressure is applied to said exposed surface of said second area, at a rate which exceeds the rate of movement ofsaid first piston means, and

manually actuated means for controlling the supply of said fluid pressure to said exposed surfaces of said first and second piston means.

2. A device as in claim 1 including magazine means for retaining a plurality of fasteners and for positioning each of said fasteners sequentially so as to be driven into said material by said driving means.

3. A device as in claim 2 wherein said second piston means includes a first differential piston having a driver blade attached for driving said fastener into said material and said first piston compressing means includes a second differential piston and a shuttle attached to said second piston for compressing this material against said support means, said shuttle having a raceway within which said fastener is driven by said driver blade.

4. A device as in claim 3 wherein said second piston is a hollow, cylindrical piston having a central cylindrical cavity, and said first piston reciprocates within said cavity.

5. A device as in claim 4 wherein said fastener is a staple.

6. A device as in claim 5 wherein said controlling means includes manually operated means having a first position causing said fluid to be directed so as to cause said pistons to move toward said material and a second position cutting off the supply of pressure fluid so that said pistons move away from said material.

7. A device as in claim 6 wherein said supporting means is a fixed clincher.

8. In a fluid-pressure-operated device having a fastener driver for driving fasteners through material a casing having an inner cavity, a shuttle having a confining raceway, and magazine means adapted to hold a plurality of fasteners and to position successive fasteners in said raceway to be driven through said material by said driver, the improvement comprising a first differential piston attached to said driver means for causing said driver to move independently and linearly within said cavity to drive said fasteners through said material when fluid pressure is applied to the top of said first piston, a second differential piston attached to said shuttle means for causing said shuttle to independently move within said cavity at a different speed from said first piston toward said material when fluid pressure is applied to the top of said second piston so that said shuttle compresses said material before said fastener is driven through said material and manually actuated valve means for applying fluid pressure to the top of said first and second pistons.

9. A device as in claim 8 wherein said fasteners are staples and said improvement includes a clincher fixed to said casing for clinching said staple after it has penetrated said material.

10. A device as in claim 9 wherein said casing includes a handle member having a chamber reservoir for containing fluid under pressure, a first passageway connecting said reservoir to a first differential chamber formed within said inner cavity and to a second differential chamber formed within said central cavity so that the fluid pressure exerts an upward force on said pistons, a bore in said casing, a second passageway connecting said bore to a third chamber formed within said inner cavity and to a fourth chamber formed within saidcentral cavity so that fluid pressure exerts a downward force on said pistons, a third passageway connecting said bore to the atmosphere and said manually actuated valve means comprises, a poppet valve which has a closure on one end and which is reciprocable in said bore, having a first position in whichsaid second and third passageways are connected together and said closure seals said bore from said reservoir and a second position in which said poppet valve closes said third passageway and permits said fluid to pass from said reservoir into said second passageway, and a manual valve trigger adapted to shift said poppet valve from said first to second position to cause said pistons to move toward said material, and from said second to said first position to cause said pistons to move away from said material. 

1. A fluid-pressure-operated device for compressing material and driving a fastener into said material comprising: housing means having means therein defining a reservoir and a cylindrical chamber, first piston means provided in said cylindrical chamber for linear movement therein, said first piston means having a cylindrical chamber and an exposed surface of a first area such that said first piston means moves in said cylindrical chamber to compress said material when fluid is applied to said exposed surface, second piston means provided in said cylindrical chamber of said first piston for linear movement at a constant angular relationship with respect to said first piston means and independently of said first piston means, said second piston means having an exposed surface of a second area such that said second piston means moves in said cylindrical chamber of said first piston to drive said fastener when fluid pressure is applied to said exposed surface of said second area, at a rate which exceeds the rate of movement of said first piston means, and manually actuated means for controlling the supply of said fluid pressure to said exposed surfaces of said first and second piston means.
 2. A device as in claim 1 including magazine means for retaining a plurality of fasteners and for positioning each of said fasteners sequentially so as to be driven into said material by said driving means.
 3. A device as in claim 2 wherein said second piston means includes a first differential piston having a driver blade attached for driving said fastener into said material and said first piston compressing means includes a second differential piston and a shuttle attached to said second piston for compressing this material against said support means, said shuttle having a raceway within which said fastener is driven by said driver blade.
 4. A device as in claim 3 wherein said second piston is a hollow, cylindrical piston having a central cylindrical cavity, and said first piston reciprocates within said cavity.
 5. A device as in claim 4 wherein said fastener is a staple.
 6. A device as in claim 5 wherein said controlling means inclUdes manually operated means having a first position causing said fluid to be directed so as to cause said pistons to move toward said material and a second position cutting off the supply of pressure fluid so that said pistons move away from said material.
 7. A device as in claim 6 wherein said supporting means is a fixed clincher.
 8. In a fluid-pressure-operated device having a fastener driver for driving fasteners through material a casing having an inner cavity, a shuttle having a confining raceway, and magazine means adapted to hold a plurality of fasteners and to position successive fasteners in said raceway to be driven through said material by said driver, the improvement comprising a first differential piston attached to said driver means for causing said driver to move independently and linearly within said cavity to drive said fasteners through said material when fluid pressure is applied to the top of said first piston, a second differential piston attached to said shuttle means for causing said shuttle to independently move within said cavity at a different speed from said first piston toward said material when fluid pressure is applied to the top of said second piston so that said shuttle compresses said material before said fastener is driven through said material and manually actuated valve means for applying fluid pressure to the top of said first and second pistons.
 9. A device as in claim 8 wherein said fasteners are staples and said improvement includes a clincher fixed to said casing for clinching said staple after it has penetrated said material.
 10. A device as in claim 9 wherein said casing includes a handle member having a chamber reservoir for containing fluid under pressure, a first passageway connecting said reservoir to a first differential chamber formed within said inner cavity and to a second differential chamber formed within said central cavity so that the fluid pressure exerts an upward force on said pistons, a bore in said casing, a second passageway connecting said bore to a third chamber formed within said inner cavity and to a fourth chamber formed within said central cavity so that fluid pressure exerts a downward force on said pistons, a third passageway connecting said bore to the atmosphere and said manually actuated valve means comprises, a poppet valve which has a closure on one end and which is reciprocable in said bore, having a first position in which said second and third passageways are connected together and said closure seals said bore from said reservoir and a second position in which said poppet valve closes said third passageway and permits said fluid to pass from said reservoir into said second passageway, and a manual valve trigger adapted to shift said poppet valve from said first to second position to cause said pistons to move toward said material, and from said second to said first position to cause said pistons to move away from said material. 